Localization of the Stem Cells Exosomes in the Brain and in the Cultured Mouse Brain Cells

Abstract—We studied the possibility of transferring exosomes of neural (NSC) and mesenchymal (MSC) mouse stem cells labeled with the fluorescent dye PKH26 into the cerebral cortex and hippocampus after their intranasal administration to mice, and the accumulation and localization of exosomes in cultured brain cells of various types, and also the effect of NSC and MSC exosomes on the parameters of the cell cycle and the level of apoptosis of cultured NSCs after irradiation at a dose of 4 Gy. The accumulation of exosomes obtained from the culture medium of NSCs and MSCs from the adipose tissue of C57BL/6 mice was shown both in the hippocampus and in the cerebral cortex after their intranasal administration to syngeneic mice. Exosomes were found predominantly in the perinuclear region of brain cells. In cultured NSCs and neurons and astrocytes differentiated from NSCs, exosomes were localized in the perinuclear region of cells and, in astrocytes, also in the cytoplasm. Exosomes accumulated most intensively in astrocytes. When studying the effect of stem cell exosomes on the cell cycle of irradiated NSCs, it was shown that the cultivation of NSCs irradiated at a dose of 4 Gy in the presence of exosomes of both NSCs and mouse MSCs did not lead to the restoration of cell cycle parameters but provided a decrease the number of apoptotic cells 24 h after exposure.